07-29-2026, 11:36 PM
Why software projects take longer
Summary
In his post, Erik Bernhardsson argues that software project delays are a statistical artifact caused by humans estimating the median time a task will take—where half of outcomes are faster and half are slower—rather than the mean (expected average time). Because software completion times follow a right-skewed, log-normal distribution—where tasks are strictly bounded at zero on the fast side but virtually unbounded on the slow side—a single task experiencing unforeseen complications can blow up by a massive factor and heavily drag down the entire timeline.
Since overall project schedules depend on adding up means rather than medians, high-uncertainty tasks quietly dominate project deadlines, making simple additive estimates consistently over-optimistic when planning complex software roadmaps.
ARTICLE
Summary
In his post, Erik Bernhardsson argues that software project delays are a statistical artifact caused by humans estimating the median time a task will take—where half of outcomes are faster and half are slower—rather than the mean (expected average time). Because software completion times follow a right-skewed, log-normal distribution—where tasks are strictly bounded at zero on the fast side but virtually unbounded on the slow side—a single task experiencing unforeseen complications can blow up by a massive factor and heavily drag down the entire timeline.
Since overall project schedules depend on adding up means rather than medians, high-uncertainty tasks quietly dominate project deadlines, making simple additive estimates consistently over-optimistic when planning complex software roadmaps.
ARTICLE
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│ KONSTANTINOS MICHAILIDIS │
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